In general, acne is caused by increased sebum production owing to increased androgen production. Specifically, sebum production by androgen and hyperkeratinization of follicles result in narrowing or and, in severe cases, blocking the follicles. When the follicle is narrowed or blocked, sebum cannot be excreted from the follicle, creating microcomedones. In these conditions, the anaerobic bacterium Propionibacterium acnes growing in the follicle may cause inflammation.
As a result of the inflammation, erythema, itching or swelling occurs and, in severe cases, hyperpigmentation may occur. If the acne is squeezed or pressed, the inflammation may aggravate as the comedone bursts. Also, it is highly likely that acne scar develops as a result of tissue damage.
The inflammatory acne may be induced by various causes. For example, various additives included in cosmetics may cause inflammatory acne when they remain on the skin. Also, sebum excreted from the body, sweat, UV, etc. may cause skin inflammations.
Currently, researches are focused only on the treatment of the inflammation caused by the inflammatory acne. However, even after the inflammation is treated, erythema or scar may remain and cause negative effects in appearance. Thus, the inventors of the present disclosure performed researches to suppress or prevent pigmentation and scarring caused by inflammatory acne.